SG Glitch or maybe a hack?

I have no idea what happened, as you can see it says that there are 2 players left, but there are 3, and i can not hit one of them, but they could hit me. Not much to say, i'm mind blown at what just happened.. xD

That is very odd :s perhaps the number of players thing glitched up, and there were really three players remaining. Did the invincible player die previously in the game?
If so, seems more like a hack than a glitch